durham@w2xo.pgh.pa.us (Jim Durham) (03/31/91)
This is a long shot, but I thought I'd try this group, as most of the 'computer' groups are software types and this is definitely a hardware question: On a DEC RQDX2 disk controller, the controller 'knows' when you are using an 'official' DEC drive (RD52,RD53). These are ST-506 drives that work just fine in PCs or whatever as ST-506 drives. The reverse is *not* true, you can't put another brand of ST-506 drive on the DEC controller. Even if the physical characteristics of the drive are the same; ie; number of heads, cylinders, etc. WHY? How do it know? It refuses to acknowledge the existance of anything but an 'official' DEC drive. There is a parameter block that is written out to the drive that will not allow one simple format program to work. I am aware of this. This isn't the problem. Anyone ever run into this and maybe *know the answer?*. I really don't want to buy another 71 meg drive just because the controller needs some edge connector pin tied high or some such thing. Thanks for reading! -Jim Durham (durham@w2xo.pgh.pa.us)
wtm@uhura.neoucom.EDU (Bill Mayhew) (03/31/91)
I am not familiar with RD53s, but DEC may use the same approach as IBM in crippling 3rd party efforts to selling generic disk drives. IBM uses the highest numbered track on the drive to hold signature information which is recorded before the drive ships. IBM's installation software looks for the information and pukes if the information is not there. I found this out when I bought a Priam 330 megabyte ESDI drive for a PS/2 mod 80, used it there, then used it for a while with a WD-1007V/SE2 controller in a generic ISA machine. After moving the drive back to the PS/2, the PS/2 would no longer recognize the drive any more because I had inadvertently wiped out the signature info. Rather annoying to say the least. One way to fake out a DEC controller might be to take a good RD53, install it in an IBM clone, and examine the highest numbered track on the drive to see if there is any interesting info there. Provided DEC uses the customary 17 sectors/track, a one might be able to use a PC utility program to move the information over to a new drive of the same type as the RD53. Bill -- Bill Mayhew NEOUCOM Computer Services Department Rootstown, OH 44272-9995 USA phone: 216-325-2511 wtm@uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm via internet: (140.220.001.001)
jeh@dcs.simpact.com (04/01/91)
In article <140@w2xo.pgh.pa.us>, durham@w2xo.pgh.pa.us (Jim Durham) writes: > On a DEC RQDX2 disk controller, the controller 'knows' when you are > using an 'official' DEC drive (RD52,RD53). [...] I don't know about the RD52, but the RD53 is a Micropolis 1325 or 1335 (DEC has used both) with a wire jumper installed in the normally-empty "R7" position on the PC board. My company has bought a couple of these drives and run them on RQDX2, RQDX3, and the integrated controller in a MicroVAX 2000. (Note that the RQDX2's format is different from the latter two.) As for why other drives with identical geometry won't work, I can't say. It must have something to do with that R7 jumper. Does anyone know what the jumper does? --- Jamie Hanrahan (x1116), Simpact Associates, San Diego CA Chair, VMS Internals Working Group, U.S. DECUS VAX Systems SIG Internet: jeh@dcs.simpact.com, or if that fails, jeh@crash.cts.com Uucp: ...{crash,scubed,decwrl}!simpact!jeh
jeh@dcs.simpact.com (04/02/91)
In article <1991Mar31.223248.2242@dcs.simpact.com>, jeh@dcs.simpact.com writes: > In article <140@w2xo.pgh.pa.us>, durham@w2xo.pgh.pa.us (Jim Durham) writes: >> On a DEC RQDX2 disk controller, the controller 'knows' when you are >> using an 'official' DEC drive (RD52,RD53). [...] > > I don't know about the RD52, but the RD53 is a Micropolis 1325 or 1335 (DEC > has used both) with a wire jumper installed in the normally-empty "R7" position > on the PC board. ... Credit where credit is due: The above information (which I posted) is from Terry Kennedy @ St. Peters' College. On DECUServe there is a whole thread devoted to making non-DEC drives behave as RDxx and similar, which Terry started. Following my sig is his note on the RD53. --- Jamie Hanrahan (x1116), Simpact Associates, San Diego CA Chair, VMS Internals Working Group, U.S. DECUS VAX Systems SIG Internet: jeh@dcs.simpact.com, or if that fails, jeh@crash.cts.com Uucp: ...{crash,scubed,decwrl}!simpact!jeh <<< EISNER::DUA3:[NOTES$LIBRARY]HARDWARE_HELP.NOTE;1 >>> -< HARDWARE_HELP >- ================================================================================ Note 93.2 Low-end disk devices - The Digital difference 2 of 62 EISNER::KENNEDY "Terry Kennedy" 25 lines 16-JAN-1988 01:37 -< RD53 >- -------------------------------------------------------------------------------- The DEC RD53 is a Micropolis 1325 or 1335 drive with one mod- ification. Earlier units were 1325s, current units are 1335s. The modification is as follows [yes, it will probably void your warranty]: Turn the drive over so that the logic board is facing you. Locate the two slotted screws and loosen them. Lift the drive logic board up gently (it is hinged). Toward the hinge end, locate the empty location marked R7. Solder a jumper in. You now have a RD53. You will need to move the drive select jumper to either 3 (for DU0 or expansion cabinet) or 4 (for DU1). One word of caution - if you are re-using your old drive's skid plate (the slide mount bracket), be sure to tape over the metal on the front end of the bracket or it will short out the drive. DEC's RD53 skid plates have foam covering the metal.